Gaseous electric discharge device



Patente d Feb. 11, 1936 UNITED STATES PATENT OFFICE 2,030,414 I GASEOUS ELECTRIC DISCHARGE DEVICE poration of New York Application June 26, 1934, Serial No. 732,490

In the Netherlands July 4, 1933 6 Claims. (01. 176-124) The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to starting and operating circuits for such devices.

The starting voltage of gaseous electric discharge devices is higher than the operating voltage thereof. The higher starting voltage can be supplied to such devices by connecting a choke-coil in series therewith and a condenser in parallel therewith, the choke-coil and the condenser being so proportioned with respect to each other that they are in resonance for the fundamental frequency of the altemating current source to which said discharge device is connected. Such a circuit is not satisfactory for gaseous electric discharge devices having thermionic electrodes, i. e., electrodes which are electron emitting when heated, because the condenser shortens the life of this type of electrode, 20 which causes rapid depreciation of the gaseous electric discharge device, and the discharge itself is very irregular.

The object of the present invention is to provide a starting and operating circuit for a gaseous electric discharge device, said circuit comprising a choke-coil connected in series with the device and a condenser connected in parallel with the device whereby the above disadvantages are avoided. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description. We have discovered that the above object is attained when the condenser and the choke-coil are in resonance for a higher harmonic (preferably the third harmonic) rather than for the fundamental frequency of the alternating current source for the discharge device. The irregularity in the discharge and the harmful effects on the thermionic electrode is eliminated in such a circuit. When the voltage of the current source has no higher harmonics special means can be used in the circuit for creating higher harmonics. A choke-coil having a highly saturated iron core, which type of choke-coil generates higher harmonies, particularly the third harmonic, is useful for this purpose.

, When desired, an auxiliary gaseous electric discharge device is connected into the above de- 50 scribed circuit to generate the higher harmonics or an auxiliary discharge path is provided in the main gaseous electric discharge device for the same purpose. In the latter arrangement the auxiliary gaseous electric'discharge not only produces the higher harmonics but also ionizes the gaseous filling in the discharge device to facilitate the starting of the main discharge therein. When the gaseous electric discharge is of the type having two main discharge supporting thermionic electrodes in spaced relation, an auxil- 5 iary electrode is mounted adjacent each of said thermionic electrodes and each of said auxiliary electrodes is connected to a condenser which is tuned to a choke-coil fora higher harmonic. The condenser is connected to the main electrode re- 1Q mote from the auxiliary electrode connected to said condenser. When desired one condenser, connected betwei the two auxiliary electrodes, is used.

When an auxiliary gaseous electric discharge 15 device is used to produce the higher harmonics said auxiliary discharge device is utilized to cut the condenser out of circuit during the operation of the main discharge device, when desired, as disclosed in the copending application Serial 20 Number 728,765, filed June 2, 1934, the inventor being Lourens Blok. In the application referred to the choke-coil is connected in series with the main discharge device, a condenser is connected in parallel to said main discharge device and an auxiliary gaseous electric discharge device is connected in series with said condenser. The auxiliary gaseous electric discharge device is startable on the voltage of the current source for the circuit but the voltage applied thereto after the main discharge device has been started into operation is insuflicient to maintain the auxiliary device in operation and the condenser is cut out of circuit. Other means, such as a bi-metallic element, is used to cut the condenser out of circuit during the operation of the main discharge device, when desired.

In the drawing accompanying and forming part of this specification severalembodiments of the invention are shown, in which, I

Fig. 1 is a schematic view of one embodiment of the invention,

Fig. 2 is a similar view of another embodiment of the invention,

Fig. 3 is a similar view of still another embodiment of the invention, and

Fig. 4 is a similar view of another embodiment of the invention.

Referring to Fig, 1 of the drawing the new and novel starting and operating circuit consists of a tubular gaseous electric discharge device I having a gaseous filling therein, such as neon, and having a thermionic-electrode 2 at each end thereof.

' Said electrodes 2 consist of a coiled filament, such as a tungsten or nickel filament, coated 01:, im- 55 pregnated with an electron emitting material, such as barium oxide. Said discharge device I is connected to the terminals 3 of an alternating current source of commercial voltage, such as 110 or 220 volts. A choke-coil 4 isconnectedin series with said discharge device I and a condenser 5. is connected in parallelwith said device I. The condenser 5 and the choke-coil 4 are of such dimensions with respect to each other that they are in resonance for a high harmonic of the alternatingcurrent source. When the frequency of the alternating current source is 50 cycles, for example, the self-inductance of the choke-coil 4 is 0.6 henry and the capacitance of the condenser said condenser 5 to produce the higher harmonics,

v tion of thedischarge device.

when desired. In such an apparatus the auxiliary gaseous electric discharge device 20 is utilized to cut the condenser 5 out of circuit during the operation of said main discharge device I and said auxiliary device 20 is startable on the voltage of the current source and inoperable on the voltage applied thereto after said main device I has been started into operation.

The embodiment of the invention illustrated in Fig. 2 of the drawing consists of a U-shaped gaseous electric discharge device having main discharge supporting thermionic electrodes 1 and 8 sealed therein at the ends thereof and hollow, open-ended cylindrical auxiliary electrodes 9 and I8 surrounding said main electrodes I and 8 respectively. When desired,'said auxiliary electrodes 9 and I8 are thermionic electrodes. The gaseous filling of said discharge device 6 consists of a rare gas, such as neon, and a difficultly vaporizable tor to reduce the heat radiated by the lamp 6 and thus maintain an effective vapor pressure of the difilcultly vaporizable material during the opera-- 7 A 'double walled jacket having the space between the walls thereof evacuated is suitable for this purpose.

The main electrode 1 is connected to said auxiliary electrode I8 through a condenser II. Similarly the'main electrode 8 is connected to the auxiliary electrode 9 through the condenser I2. Said main electrode 1 is connected to one end of the choke-coil I3 and the other end of said chokecoil I3 is,connected to a terminal ll of an alternating current source. The main electrode 8 is connected to'the other terminal II of said current source.

Two circuits are thus connected in parallel with the main discharge between the main electrodes I and 8. One circuit consists of the condenser I2 and the auxiliary discharge between the main electrode I and the auxiliary electrode 8 while the other circuit consists of the condenser II and the auxiliary discharge between the main electrode 8 and the auxiliary electrode I8. Said choke-coil I3 is connected in series with both of said circuits. Each oi. said condensers I I and I2 are of such size with respect to said choke-coil I3 that each of said condensers II and I2 and said choke-coil I3 are in resonance for the third harmonic of the alternating current source. The presence of an auxiliary discharge in each of the circuits comprising a choke-coil and a condenser is favorable for generating the third harmonic.

The thermionic electrodes of the discharge de-' vices I and 6 are heated to an electron emitting temperature by'separate heating currents, when desired, or said electrodes are heated to this temperature solely by the discharge, when desired. When said electrodes are heated solelyby the discharge the auxiliary discharges in said device 6 serve to heat the electrodes to such temperature.

The starting of the main discharge in the above described embodiments of the invention is positive and quick and the difficulties encountered in prior circuits wherein the choke-coil and the condenser are so proportioned that they are in resonance for the fundamental frequency of the alternating current source to which said discharge device is connected are avoided.

The embodiment of the invention illustrated in I Fig. 3 of the'drawing is similar in all respects to that shown in Fig. 2 except that in this embodiment only one condenser I5 is connected between the auxiliary electrodes 9 and I0. A circuit comprising two discharge paths and the condenser I5 is thus formedwhich circuit is connected in parallel. with the main discharge path between the electrodes 1 and 8.

The embodiment of the invention illustrated in Fig. 4 of the drawing is similar in all respects to that illustrated in Fig. 1 except that in this embodiment the choke-coil is of a different type. The choke-coil in this embodiment of the invention has an iron core having two legs I 6 and II of difierent thicknesses having coils I8 and I8 wound thereon, respectively. -The leg I6 is considerably thinner than the leg II. The two coils I8 and I9 of the choke-coil are connected in series and are wound in such manner that the current traversing said coils I8 and I9 producesopposite fluxes in the core. The coil I9 is connected in series with the device 1. After current is applied to the circuit and before the discharge device I has started'i'nto operation current flows through coil I8 of the choke-coil and. the condenser 5 which are connected in series. The leg I6 is of such size that during this period it is highly saturated and a. strong third harmonic is produced. After the discharge device I has been started into operation a weaker flux is present in the; core 'which is desirable in view of the higher current.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes Letters Patent of the United States is:-

1. A circuit for starting and operating a gaseous electric" discharge device comprising in combination, a condenser connected in parallel with said device, a choke-coil connected in series with said device, a current source for said device, said chokecoil and said condenser being so proportioned with respect to each other that they are in resonance for a higher-harmonic of the alternating current source.

2. A circuit for starting and operating a gaseous electric discharge device comprising in combination, a condenser connected in parallel with said device, an auxiliary discharge connected in series with said condenser, a choke-coil connected in series with said device, a current source for said device, said choke-coil and said condenser being so proportioned with respect to each other that they are in resonance for a higher harmonic of the alternating current source produced by said auxiliary discharge.

3. A circuit for starting and operating a gaseous electric discharge device comprising in combination, a condenser connected in parallel with said device, a choke-coil connected in series with said device, an auxiliary gaseous electric discharge device connected in series with said condenser, a current source for said first named device, said choke-coil and said condenser being so proportioned with respect to each other that they are in resonance for a higher harmonic of the alternating current source produced by said auxiliary device.

4. A circuit for starting and operating a gaseous electric discharge device comprising in combination, a condenser connected inparallel with said device, a choke-coil connected in series with said device, an auxiliary gaseous electric discharge device connected in series with said condenser, a current source for said first named device, said choke-coil and said condenser being so proportioned with respect to each other that they are in resonance for a higher harmonic of the alternating current source produced by said auxiliary device, said auxiliary discharge device being startable on the voltage of the current source and inoperable on the voltage applied with said device, a current source for said deviceand a condenser connected in series with one of the auxiliary discharges in said device, said choke-coil and said condenser being so proportioned with respect to each other that they are in resonance for a higher. harmonic of the alternating current source produced by said auxiliary discharge.

. 6. A circuit for starting and operating a gaseous electric discharge device comprising in combination, a condenser connected in parallel with said device, a choke-coil connected in series with said device, a current source-for said device, said choke-coil having at least two legs of different thickness and a coil wound on each of said legs, said coils being wound in opposing directions and being connected in series, the coil wound on the thinner leg being connected in series with said condenser directly and in series with said device through the coil on the thicker leg, said thinner legand said condenser being so proportioned with respect to each' other'that they are in resonance for a higher harmonic of the current source.

WILLEM UYTERHOEVEN. CORNELIS VERBURG. EDUARD G. DORGELO. 

